21170420 has 24 divisors (see below), whose sum is σ = 45024000. Its totient is φ = 8360352.

The previous prime is 21170417. The next prime is 21170431. The reversal of 21170420 is 2407112.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5120 + ... + 8279.

It is an arithmetic number, because the mean of its divisors is an integer number (1876000).

Almost surely, 2^21170420 is an apocalyptic number.

21170420 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21170420 is an abundant number, since it is smaller than the sum of its proper divisors (23853580).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21170420 is a wasteful number, since it uses less digits than its factorization.

21170420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13487 (or 13485 counting only the distinct ones).

The product of its (nonzero) digits is 112, while the sum is 17.

The square root of 21170420 is about 4601.1324692949. The cubic root of 21170420 is about 276.6367187467.

Adding to 21170420 its reverse (2407112), we get a palindrome (23577532).

The spelling of 21170420 in words is "twenty-one million, one hundred seventy thousand, four hundred twenty".